Cho hình thang ABCD có AB // CD . Góc A = góc D = 90 độ , hai đường chéo AC vuông góc với BD tại O , OD = 8 cm , OB = 2 cm .Tính diện tích ABCD

Cho tam giác ABC vuông tại A . AB/AC = 8/15 và BC 17 cm , đường cao AH . Tính các cạnh tam giác ABC và AH , CH , BH

Cho tam giác ABC có đường cao AH , biết AH = 4 cm , BH/HC = 1/4 . Tính các cạnh AB , AC , BC , BH , HC

Exercise 6. Give the correct form of the words given to complete the sentence.

      1.   Horror films                             my younger sister.                                                       TERRIBLE

      2.   I don’t think it is good for young kids to see               on TV.                                     VIOLENT

      3.   We are going to the cinema to see an              film.                                                     AMAZED

      4.   Although Titanic is a                           film, it has a sad ending.                                  ROMANCE

      5.   He falls in love with a pretty girl. It’s a beautiful                     .                                   ROMANTIC

      6.   His recent film received a lot of                       from the public.                                   CRITIC

      7.   My favourite                            -fiction films have being from Mars.                           SCIENTIST

      8.   I don’t like horror films because they are too for me.                                     FRIGHT

      9.   Dracula is the best                               film I’ve ever seen.                                          IMPRESS

      10. Do you know Daniel Day-Lewis? He has won three Oscars for                                ACT

            Best                 .

Exercise 7. Complete the following sentences with the correct form of the words in brackets.

      1.   There are many                        differences between the two communities.                 (culture)

      2.   Streets are decorated with                                lights and red banners.                        (colour)

      3.   There were lively New Year                           all over the town.                                (celebrate)

      4.   It is                  in America to eat turkey on Thanksgiving Day.                                  (tradition)

      5.   Vietnam’s New Year is                        according to the Lunar calendar.                    (celebrate)

      6.   What forms of                          do you participate in during the festival?                    (entertain)

      7.   Her eyes were wide with                                  when she heard the news.                  (excite)

      8.   The Chinese New Year marks the                               of spring and the start

            of the Lunar New Year.                                                                                              (begin)

Exercise 8. Give the correct form of the words given to complete sentences.

      1.   We should use them                            and try to find out                                            ECONOMY                     alternative sources of power.

      2.   Solar energy is                         , plentiful and clean.                                                    RENEW

      3.   I think that solar energy can be an                               source of                                  ALTER                            energy in the near future.

      4.   We should reduce the use of                           at home.                                               ELECTRICAL

      5.   It’s a clean source of energy. Sailboats couldn’t move without                                   POWERFUL                   this             .

      6.   Waves will be used as an                    friendly source of energy.                                ENVIRONMENT

      7.   Limit car trips by relying on biking, walking, public                                                   TRANSPORT                                   .

      8.   Solar power can be used to                             or cool our houses.                              HOT

      9.   Energy is used to                     a lot of electrical things.                                               PRODUCT

      10. There will be a                        of energy in the near future.                                        SHORT

Exercise 9. Give the correct form of the words given to complete sentences.

      1.   I don’t think so. The solar panels are becoming                      and easy to install.       CHEAP         

      2.   Scientists are looking for clean and                             sources            of energy.                   EFFECT       

      3.   I know it is also clean and safe to the environment. But does it cost a lot of money

      to install the                                   panels on the roofs?                                                     SUN

      4.   More renewable energy sources will be used to solve the problem of _____. POLLUTE    

      5.   Because our major sources of energy are running out while                                       LIMIT                              the solar energy is abundant and               .

      6.                           , fossil fuels are harmful to the environment.                                       FORTUNATE

      7.   Energy is used to produce a lot of                               things.                                      ELECTRICAL

      8. The                                of wind turbines will be completed by next Friday.               INSTALL     

      9.   It can be found in only some places of the earth. It comes                                          DEEP                               from                                   inside the earth.

      10.                         particles reach the Earth in just 8 minutes.                                          ENERGY

Exercise 10. Supply the correct form of the word to complete the sentence.

      1.   We want to buy                                    that will save money.                                      (product)

      2.   These                           will conserve the earth’s resources.                                         (innovate)

      3.   D. E Huges was the                            of microphone.                                                (invent)

      4.   The price of                             has gone up again.                                                      (electric)

      5.   People in the countryside is                             .                                                           (friend)

      6.   If it doesn’t rain soon, there’ll be a great                                 of water.                     (short)

      7.   Environmental                         is every body’s responsibility.                                    (protect)

      8.   Taxi drivers have to have good                       on the street names.                            (know)

      9.   In the future, many buildings will be                           by solar energy.                      (hot)

      10. My brother can repair electric                          very well.                                           (apply)

Exercise 11. The word at the end of each of the following sentences can be used to form a word that fits suitably in the blank.

      1.   The first symptom of the disease is a very high                                   .                       TEMPERATE

      2.   The long hot summer has led to serious water                                     .                       SHORT         

      3.   To have hundreds of                           people sleeping in                                            HOME                        the streets of a rich city like London is a crime.

      4.   Average                       for skilled workers are rising.                                                  EARN

      5.   We lived in rented                               before buying  this house.                               ACCOMMODATE 

      6.   Drought has                             many countries in Africa                                             AFFECT                          after a long period of dry weather.

      7.   Nuclear power can be used for                                     or military purposes.               PEACE                      8.      The government is trying to limit population                     .                                               GROW

      9.   A megacity is a very large city with big                      .                                               POPULAR

      10. Healthcare workers who offer                         care to                                                  MEDICINE                     others are some of the lowest paid people in the country.